Projection-type display apparatus and control method for projection-type display apparatus as well as control program for Projection-type display apparatus

ABSTRACT

Exemplary embodiments provide a projection-type display apparatus, which can address or realize a reduction in weight and size, a reduction in power consumption, and a reduction in noise, and address or realize a reduction in price, and a control method for the projection-type display apparatus, as well as a control program for the projection-type display apparatus. The projection-type display apparatus includes a solid-state light source that emits light, a mirror device that controls an emitting direction of the incident light to thereby subject the incident light to temporal modulation, and a projecting device that projects the modulated light.

This is a Continuation of application Ser. No. 12/565,388 filed Sep. 23,2009, which is a Divisional of application Ser. No. 12/081,980 filedApr. 24, 2008, which is a Continuation of application Ser. No.11/699,399 filed Jan. 30, 2007, which is a Continuation of applicationSer. No. 11/041,455 filed Jan. 25, 2005. The disclosures of the priorapplications are hereby incorporated by reference herein in theirentirety.

BACKGROUND

Exemplary embodiments of the present invention relate to aprojection-type display apparatus, and a control method for theprojection-type display apparatus, as well as a control program for theprojection-type display apparatus.

A related art projection-type display apparatus (projector) uses amirror device, such as a DMD (digital micro-mirror device; registeredtrademark) of Texas Instruments Incorporated as a light modulationdevice, other than a liquid crystal display device (LCD).

As a light source for this projection-type display apparatus, a highpressure mercury lamp emitting white light is usually used. Theprojection-type display apparatus separates the emitted white light intoR, G, and B colors in a time axis direction using a color wheel, andfurther adjusts effective reflection times for the respective colorsusing respective micro-mirrors of DMD to thereby form a projection image(see, for example, “Nikkei Electronics”, Nov. 24, 2003, p. 114).

SUMMARY

However, there is a problem in that, when a thermal light sourcegenerating heat described above is used as a lighting light source,conversion efficiency to convert inputted electric power into light islow and an input voltage is high, which results in an increase of powerconsumption in the thermal light source. In addition, there is a problemin that, since the thermal light source has a large power supply and alarge lamp, a size of the projection-type display apparatus is increasedand a cooling fan with high efficiency to cool the thermal light sourceis required, which results in an increase in noise due to driving soundof the cooling fan.

In order to address or solve the above, JP-A-2003-186110 discloses atechnique that uses a light-emitting diode (LED), which emits lights ofR (red), G (green), and B (blue), as a light source. The lights of therespective colors emitted from the LED are reflected by a dichroic prismand inputted to a DMD.

However, in this method, there is a problem in that the dichroic prismis required to make the lights of the respective colors emitted from theLED uniform, which results in an increase in cost and size of aprojection-type display apparatus.

Exemplary embodiments of the invention address or solve the above, andprovide a projection-type display apparatus, which can address orrealize a reduction in weight and size, a reduction in powerconsumption, and a reduction in noise, and address or realize areduction in price, and a control method for the projection-type displayapparatus, as well as a control program for the projection-type displayapparatus.

In order to address or attain the above, a projection-type displayapparatus of an exemplary embodiment of the invention includes asolid-state light source that emits light, a mirror device that controlsan emitting direction of the incident light to thereby subject theincident light to temporal modulation, and a projecting device thatprojects the modulated light.

Since the projection-type display apparatus of exemplary embodiments ofthe invention uses the solid-state light source, such as alight-emitting diode (LED) as a light source, compared with the highpressure mercury lamp described above, it is possible to address orrealize the reduction in weight and size, the reduction in powerconsumption, and the reduction in noise of the projection-type displayapparatus, as well as the reduction in price of the projection-typedisplay apparatus.

In other words, since the solid-state light source has a low caloricvalue compared with the high pressure mercury lamp, efficiency toconvert inputted electric power into light is high. Thus, when the sameluminance is obtained, it is possible to reduce electric power to beinputted (the reduction in power consumption). It is also possible toreduce or prevent noise due to a cooling fan or the like (the reductionin noise). In addition, since the solid-state light source itself islighter and smaller than the high pressure mercury lamp, it is possibleto use a circuit to drive the solid-state light source smaller than adrive circuit for the high pressure mercury lamp. Consequently, toaddress or realize a reduction in cost of the projection-type displayapparatus, it is more advantageous to use a solid-state light sourcearray as a light source than using the high pressure mercury lamp as thelight source.

Since the solid-state light sources are arranged and used as thesolid-state light source array, light having a uniform illuminancedistribution is made incident on a surface of a mirror device that is anobject to be lighted by the light sources. Therefore, it is unnecessaryto provide the dichroic prism unlike JP-A-2003-186110. This isadvantageous to address or realize the reduction in weight and size andthe reduction in price of the projection-type display apparatus.

In order to address or realize the structure described above, morespecifically, it is desirable that the solid-state light source array isa solid-state light source array in which solid-state light sourcesemitting lights of different colors are arranged.

According to this structure, the projection-type display apparatus canemit lights of different colors from the solid-state light source arrayand form a color image by subjecting each of the lights of differentcolors to temporal modulation in the mirror device.

In addition, the solid-state light source array is formed by arrangingthe solid-state light sources that emit lights of different colors, itis unnecessary to provide a dichroic prism to synthesize lights ofdifferent colors. This is advantageous to address or realize thereduction in weight and size and the reduction of price of theprojection-type display apparatus.

In order to address or realize the structure described above, morespecifically, it is desirable that the projection-type display apparatusincludes a measuring device that measures an intensity of emitted lightfrom the mirror device and calculates a correction coefficient tocorrect the intensity of emitted light to a predetermined intensity onthe basis of the intensity of the emitted light measured by themeasuring device, and the mirror device is driven on the basis of thecorrection coefficient.

According to this structure, it is possible to control an intensity ofemitted light from the mirror device to a predetermined intensity bycontrolling to drive the mirror device. Therefore, it is possible todisplay an image of predetermined brightness without being affected byexternal factors, such as aged deterioration of the light source.

In order to address or realize the structure described above, morespecifically, it is desirable that the mirror device is formed by anarrangement of micro-mirrors that reflect incident light, a correctioncoefficient is calculated for each of the micro-mirrors, and the mirrordevice is driven for each of the micro-mirrors on the basis of thecorrection coefficient.

According to this structure, it is possible to control an intensity ofemitted light from the mirror device for each of the micro-mirror.Therefore, for example, since it is possible to control emitted lightintensities of the respective colors from the mirror device topredetermined intensities, it is possible to control a color balance ofa projected image to a predetermined balance.

In order to address or realize the structure described above, morespecifically, a measuring device may be arranged detachably insertableon a light path between the mirror device and the projecting device.

According to this structure, when an emitted light intensity is notmeasured by the measuring device, it is possible to detach the measuringdevice from the light path and discourage or prevent decline in an imagequality without affecting a projected image. In addition, when anemitted light intensity is measured, since the measuring device isinserted in the light path to measure the emitted light intensity, it ispossible to directly measure emitted light to be projected (modulatedlight) and measure an accurate modulated light intensity. Therefore, itis also possible to calculate a correct correction coefficient andcontrol an intensity of modulated light to a predetermined intensityaccurately.

In order to address or realize the structure described above, morespecifically, the projection-type display apparatus may include a lightguiding device that guides reflected light emitted from the mirrordevice to the projecting means, between the mirror device and theprojecting device, and the measuring device and a reflecting plate maybe arranged to be replaceable with each other.

According to this structure, when an emitted light intensity is measuredby the measuring device, it is possible to directly measure emittedlight to be projected (modulated light) and measure an accuratemodulated light intensity by arranging the measuring device and thelight guiding device to be replaced with each other. Therefore, it isalso possible to calculate an accurate correction coefficient andcontrol an intensity of modulated light to a predetermined intensityaccurately. In addition, since the measuring device is arranged to bereplaced with the original light guiding device when a modulated lightintensity is not measured, it is possible to discourage or prevent themeasuring device from being deteriorated by incident light.

In order to address or realize the structure described above, morespecifically, the projection-type display apparatus has a reflectingplate, which reflects modulated light emitted from the mirror device tothe projecting device, between the mirror device and the projectingdevice, the reflecting plate may be a light-transmissive reflectingplate that transmits a part of incident light, and the measuring devicemay be arranged in a position where the measuring device is capable ofmeasuring the light transmitted through the reflecting plate.

According to this structure, since the measuring device measures amodulated light intensity transmitted through the reflecting plate, themeasuring device never affects an image to be projected, and it ispossible to discourage or prevent decline in an image quality. Inaddition, since a modulated light intensity can be measured by themeasuring device even while an image is projected, it is possible toalways discourage or prevent decline in an image quality.

In order to address or realize the structure described above, morespecifically, the projection-type display apparatus may include anabsorbing member that absorbs emitted light not made incident on theprojecting device in the emitted light from the mirror device, and themeasuring device and the absorbing member may be arranged to bereplaceable with each other.

According to this structure, the measuring device and the reflectingplate are arranged to be replaced with each other when an emitted lightintensity is measured by the measuring device, whereby it is possible tomeasure an intensity of emitted light not made incident on theprojecting device (ineffective light). Since the ineffective light andthe modulated light are in a one-to-one relation, it is possible tocalculate a correction coefficient of the modulated light on the basisof the intensity of the ineffective light and control an intensity ofthe modulated light to a predetermined intensity.

Since an intensity of the ineffective light is measured, intensitymeasurement for the ineffective light can be performed even while animage is projected. Thus, it is possible to discourage or prevent themeasuring device from being deteriorated.

In addition, since the absorbing member is always caused to absorb theineffective light by the projecting device when the ineffective light isnot measured, it is possible to discourage or prevent the measuringdevice from being deteriorated.

In order to address or realize the structure described above, morespecifically, the projection-type display apparatus may include anabsorbing member that absorbs emitted light not made incident on theprojecting device in the light emitted from the mirror device, and themeasuring device may also function as the absorbing member.

According to this structure, since the measuring device also functionsas the absorbing member, an intensity of ineffective light can bemeasured by the measuring device even while an image is projected. Thus,it is possible to always discourage or prevent decline in an imagequality.

In addition, it is unnecessary to provide both the measuring device andthe absorbing member, which is advantageous to address or realize areduction in weight and size of the projection-type display apparatus.

In order to address or realize the structure described above, morespecifically, the projection-type display apparatus may include anabsorbing member that absorbs emitted light not made incident on theprojecting device in the light emitted from the mirror device, and themeasuring device may be arranged to be detachably insertable on a lightpath between the mirror device and the absorbing member.

According to this structure, the measuring device is inserted on thelight path between the mirror device and the absorbing member when anemitted light intensity is measured by the measuring device, whereby itis possible to measure an intensity of ineffective light. Further, it ispossible to calculate a correction coefficient of modulated light on thebasis of the intensity of the ineffective light and control an intensityof modulated light to a predetermined intensity.

Since an intensity of the ineffective light is measured, intensitymeasurement for the ineffective light can be performed even while animage is projected. Thus, it is possible to always discourage or preventdecline in an image quality.

In addition, since the absorbing member is always caused to absorb theineffective light when the ineffective light is not measured, it ispossible to discourage or prevent the measuring device from beingdeteriorated.

A control method for a projection-type display apparatus of an exemplaryembodiment of the invention is a control method for a projection-typedisplay apparatus that includes a solid-state light source arrayincluding solid-state light sources emitting light, a mirror device thatcontrols an emitting direction of light made incident from thesolid-state light source array to thereby subject the incident light totemporal modulation, and projecting device that projects the modulatedlight. The method includes: measuring an intensity of the modulatedlight emitted from the mirror device; calculating a correctioncoefficient to correct the intensity of the modulated light to apredetermined intensity; and controlling to drive the mirror device onthe basis of the calculated correction coefficient.

The control method for a projection-type display apparatus of anexemplary embodiment of the invention can control an intensity ofemitted light from the mirror device to a predetermined intensity bycontrolling to drive the mirror device. Therefore, it is possible todisplay an image of predetermined brightness without being affected byexternal factors, such as aged deterioration of a light source.

An exemplary embodiment of the invention provides a control program fora projection-type display apparatus that includes a solid-state lightsource array including solid-state light sources emitting light, amirror device that controls an emitting direction of light made incidentfrom the solid-state light source array to thereby subject the incidentlight to temporal modulation, and a projecting device that projects themodulated light. The program includes: a program for measuring anintensity of the modulated light emitted from the mirror device; aprogram for calculating a correction coefficient to correct theintensity of the modulated light to a predetermined intensity; and aprogram for controlling to drive the mirror device on the basis of thecalculated correction coefficient.

The control program for a projection-type display apparatus of anexemplary embodiment of the invention can control an intensity ofemitted light from the mirror device to a predetermined intensity bycontrolling to drive the mirror device. Therefore, it is possible todisplay an image of predetermined brightness without being affected byexternal factors, such as aged deterioration of a light source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a projection-type display apparatus inaccordance with an exemplary embodiment of the invention;

FIG. 2 is a schematic plan view showing a lighting device in accordancewith the exemplary embodiment;

FIGS. 3A and 3B are schematics explaining temporal modulation performedby a mirror device in accordance with the exemplary embodiment;

FIG. 4 is a schematic explaining temporal modulation performed by themirror device and an LED in accordance with the exemplary embodiment;

FIG. 5 is a schematic showing a structure of a drive circuit of theprojection-type display apparatus;

FIG. 6 is a schematic of a projection-type display apparatus inaccordance with another exemplary embodiment of the invention;

FIG. 7 is a schematic of a projection-type display apparatus inaccordance with still another exemplary embodiment of the invention;

FIG. 8 is a schematic of a projection-type display apparatus inaccordance with still another exemplary embodiment of the invention; and

FIG. 9 is a schematic of a projection-type display apparatus inaccordance with still another exemplary embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

A projection-type display apparatus and a control method for theprojection-type display apparatus, as well as a control method for theprojection-type display apparatus in accordance with exemplaryembodiments of the invention, are explained below with reference toFIGS. 1 to 5.

First, a projection-type display apparatus in accordance with anexemplary embodiment of the invention is explained below with referenceto FIG. 1. The projection-type display apparatus in accordance with thisexemplary embodiment is a projection-type color display apparatus thatsubjects different color lights of R (red), G (green), and B (blue)emitted from an LED array to temporal modulation with a mirror device todisplay a color image.

FIG. 1 is a schematic showing the projection-type display apparatus inaccordance with this exemplary embodiment.

As shown in FIG. 1, the projection-type display apparatus includes alighting device (solid-state light source array) 1 that emits differentcolor lights of R, G, and B, a mirror device 30 that subjects the colorlights to temporal modulation, a measuring element (measuring device) 40that measures an intensity of light emitted from the mirror device 30,and a projection lens (projecting device) 70 that projects modulatedlight subjected to the temporal modulation.

FIG. 2 is a schematic plan view showing the lighting device 1.

As shown in FIG. 2, the lighting device 1 is constituted as an LED arrayin which LEDs (solid-state light sources) 10 r, 10 g, and 10 b emittingcolor lights of R, G, and B, respectively, are arrangedtwo-dimensionally. More specifically, a column including the LEDs 10 r,10 g, and 10 b repeatedly arranged in this order in a vertical directionis formed, and a plurality of the columns are arranged in a horizontaldirection, whereby the lighting device 1 is formed. In addition, thecolumns adjacent to each other in the horizontal direction are arrangedto be shifted to the vertical direction by half an interval ofarrangement of the LEDs such that the LEDs 10 r, 10 g, and 10 b can bearranged densely. Moreover, the LEDs 10 r, 10 g, and 10 b are arranged,such that the LEDs emitting the same color lights are not adjacent toeach other.

A condensing lens 21 is arranged on a light emitting side of thelighting device 1 in order to condense respective color lights emittedfrom the lighting device 1 on the mirror device 30 that is an object tobe lighted. A relay lens 22, which guides the respective color lightsemitted from the lighting device 1 to the mirror device 30, is alsoarranged on the light emitting side of the lighting device 1.

As described above, the condensing lens 21 and the relay lens 22 may bearranged between the lighting device 1 and the mirror device 30. Anintegrator lens such as a fly-eye lens or a rod lens, which makes anilluminance distribution of the respective color lights emitted from thelighting device 1, may be arranged additionally.

The mirror device 30 has micro-mirrors corresponding to pixels of animage arranged, in a matrix shape and is arranged such that anorientation of reflection surfaces of the micro-mirrors can be changed(so as to be able to swing). The mirror device 30 can subject therespective color lights to temporal modulation to divide the respectivecolor lights into modulated light to be projected and displayed andineffective light to be absorbed and control a ratio of the modulatedlight to 0% to 100% by controlling emitting directions of incidentrespective color lights on the basis of a video signal subjected tosignal processing.

An absorbing member 45 is arranged to absorb the ineffective lightemitted from the mirror device 30 and is arranged to be replaceable witha measuring element 40 described below.

A prism 50, which guides light emitted from the mirror device 30 to aprojection lens 70, is arranged on a path of modulated light between themirror device 30 and the projection lens 70. The prism 50 has astructure in which triangle prisms are bonded, and a mirror surfacereflecting the modulated light is formed on an inner surface thereofdiagonally. In addition, a reflecting plate (light guiding device) 51 isarranged on a surface that is opposed to the mirror surface of the prism50 and adjacent to the surface on which the modulated light is madeincident.

The measuring element 40 is arranged to be replaceable with theabsorbing member 45 and is arranged to be capable of measuring anintensity of ineffective light from the mirror device 30. In addition,the measuring element 40 includes photosensors, such as charge coupleddevices (CCDs) or CMOSs arranged in a matrix shape.

The projection lens 70 is arranged to project modulated light emittedfrom the prism 50 on a screen 71 in enlargement.

Next, an action in projection of an image by the projection-type displayapparatus including the structure described above is explained below.

First, when an image is projected, as shown in FIG. 1, the absorbingmember 45 is arranged to absorb ineffective light from the mirror device30.

As shown in FIGS. 1 and 2, the LEDs 10 r, 10 g, and 10 b of the lightingdevice 1 are turned on in a time division manner for each of the colorlights of R, G, and B. The respective color lights emitted from thelighting device 1 in a time division manner are made incident on themirror device 30 via the condensing lens 21 and the relay lens 22.

The respective color lights made incident on the mirror device 30 aresubjected to temporal modulation for each of the micro-mirrors on thebasis of a video signal inputted to the projection-type displayapparatus. Modulated light is reflected to the prism 50 and ineffectivelight is reflected to the absorbing member 45.

The modulated light emitted from the mirror device 30 is made incidenton the prism 50, reflected on the mirror surface in the prism 50 to bemade incident on the reflecting plate 51, and reflected to theprojection lens 70.

The light reflected in the direction of the projection lens 70 is madeincident on the projection lens 70 and projected on the screen 71 inenlargement.

Here, a method of temporally modulating the modulated light modulated byone micro-mirror of the mirror device 30 so as to have a predeterminedintensity is explained below.

FIG. 3A is a schematic showing intensities of the respective colorlights, which are made incident on the micro-mirror, in the case inwhich the LEDs are lighted for a fixed time. FIG. 3B is a schematicshowing intensities of modulated lights modulated by the micro-mirror ina predetermined frame.

When the LEDs 10 r, 10 g, and 10 b are lighted for a fixed time, asshown in FIG. 3A, the respective color lights of R, G, and B are madeincident on the micro-mirror of the mirror device 30 at respectiveintensities. An intensity balance of the respective color lights of R,G, and B in this state indicates white. From this state, the intensitybalance of the respective color lights of R, G, and B is changed to anintensity balance of the respective color lights of R, G, and B, forexample, shown in FIG. 3B to display a predetermined color.

FIG. 4 is a schematic showing timing of lighting control for the LEDsand timing of time control for the micro-mirror.

The method of changing an intensity balance of the respective colorlights of R, G, and B according to the temporal modulation isspecifically described below.

First, a timing signal for the micro-mirror is inputted (ON) to drivethe mirror device, such that reflected light of the micro-mirrorcorresponding to the color light R is made incident on the prism 50. Atthis point, the micro-mirror is driven upon the input of the timingsignal and an angle of the micro-mirror is changed from an angle θ1 atwhich the reflected light is made incident on the absorbing member 45 toan angle θ2 at which the reflected light is made incident on the prism50. It takes time to change the angle of the micro-mirror from the angleθ1 at which the reflected light is made incident on the absorbing member45 to the angle θ2 at which the reflected light is made incident on theprism 50. This time is defined as a mirror rotation time Tr.

The LED 10 r emitting the color light R is turned on after the mirrorrotation time Tr has elapsed from the input of the timing signal. Thisstate is maintained for a predetermined time.

Then, the timing signal is turned OFF after the predetermined time haselapsed. Consequently, the LED 10 r is turned off and the micro-mirroris driven, such that an orientation of the micro-mirror is at the angleθ1 at which the reflected light is made incident on the absorbing member45. It is possible to perform such drive control for the micro-mirror ofthe mirror device 30 in an order of about 5000 Hz.

The control described above is also performed for the remaining colorlights G and B to change an intensity balance of the respective colorlights of R, G, and B.

The drive method for the projection-type display apparatus in accordancewith this exemplary embodiment is explained below.

FIG. 5 is a schematic showing a structure of a drive circuit of theprojection-type display apparatus in accordance with this exemplaryembodiment.

First, a method of acquiring a correction parameter to correct anintensity of modulated light emitted from the mirror device 30 to apredetermined intensity using the measuring element 40 is explainedbelow.

First of all, as shown in FIG. 1, the measuring element 40 is arrangedinstead of the absorbing member 45, such that ineffective light from themirror device 30 is made incident on the measuring element 40.

As shown in FIG. 5, a control unit 82 controls the LEDs 10 r, 10 g, and10 b for each of the color lights so as to light at a constant voltagefor a fixed time. Then, the control unit 82 controls ineffective lightemitted by a predetermined micro-mirror of the mirror device 30 so as tobe made incident on the measuring element 40 for a fixed time. Thecontrol unit 82 can acquire a correction parameter for each of themicro-mirrors by performing control as described above.

The measuring element 40 outputs a signal corresponding to an intensityof the incident ineffective light to a mirror device reflection lightmeasuring unit 41, and the mirror device reflection light measuring unit41 calculates an intensity of modulated light from the intensity of theineffective light.

The calculation of an intensity of modulated light is performed for allthe color lights and all the micro-mirrors.

The intensity of the modulated light obtained by the method describedabove is inputted to the control unit 82. The control unit 82 calculatescorrection parameters to control an effective reflection time of themicro-mirrors in the respective color lights based on the intensity ofthe modulated light such that a target white color (e.g., 8300° K in acolor temperature) is obtained when the modulated lights of R, G, and Bfrom the respective micro-mirrors are subjected to time integration.

Then, the control unit 82 outputs the calculated correction parametersin the respective micro-mirrors to a correction parameter storing unit83 and causes the correction parameter storing unit 83 to store thecorrection parameters.

Next, a method of driving the projection-type display apparatus on thebasis of a video signal and a control program for the projection-typedisplay apparatus are explained below.

In this exemplary embodiment, as shown in FIG. 5, for example, a videosignal, which is an analog signal, outputted from a PC, a DVD, a TVantenna, or the like is inputted to an A/D conversion unit 81, convertedinto a digital signal, and inputted to the control unit 82.

When a video signal to be inputted to the projection-type displayapparatus is a digital signal, the A/D conversion unit 81, whichconverts an analog signal into a digital signal, is unnecessary, and adigital signal may be inputted to the control unit 82 directly. Inaddition, when a video signal to be inputted to the projection-typedisplay apparatus is compressed data, such as MPEG2 data, a decoderunit, which decodes compressed data, may be provided instead of the A/Dconversion unit 81 to input a compressed signal to the decoder unit, ora decode function may be given to the control unit 82 to input acompressed signal to the control unit 82.

The control unit 82 generates a modulation control signal, which isoutputted to the mirror device 30, on the basis of the video signalconverted into the digital signal and the correction parameters storedin the correction parameter storing unit 83. The generated modulationcontrol signal is outputted to a mirror device driver 29, and the mirrordevice driver 29 controls to drive the respective micro-mirrors of themirror device 30 on the basis of the modulation control signal

At the same time, the control unit 82 generates a light source controlsignal to control turning on and off of the LEDs 10 r, 10 g, and 10 b onthe basis of the video signal converted into the digital signal and thecorrection parameters stored in the correction parameter storing unit83. The generated light source control signal is outputted to an LEDpower supply control unit 84, and the LED power supply control unit 84controls turning on and off of the respective LED 10 r, 10 g, and 10 bvia an LED driver 85.

Correction parameters may be acquired only once when the projection-typedisplay apparatus is manufactured and shipped or may be acquiredperiodically even after the shipment.

In the method of acquiring correction parameters only once when theprojection-type display apparatus is shipped, since the measuringelement 40 is never used after the shipment, it is possible to removethe measuring element 40 and address or realize a reduction in weightand size and a reduction in price of the projection-type displayapparatus easily.

In the method of acquiring correction parameters periodically even afterthe shipment, it is possible to cope with a change in a color balance orthe like due to aged deterioration of the LEDs 10 r, 10 g, and 10 b andthe mirror device 30 and maintain a high quality image easily.

As described above, the measuring element 40 and the absorbing member 45may be arranged to be replaceable with each other, or the measuringelement 40 may also function as the absorbing member 45. According tothis structure, since intensity measurement for ineffective light can beperformed by the measuring element 40 even while an image is projected,it is possible to always discourage or prevent decline in an imagequality. In addition, it is unnecessary to provide the measuring element40 and the absorbing member 45. This is advantageous to address orrealize a reduction in weight and size of the projection-type displayapparatus.

According to the structure described above, since the LEDs 10 r, 10 g,and 10 b are used as light sources, compared with the high pressuremercury lamp described above, efficiency of converting inputted electricpower to light is high. Thus, when the same luminance is obtained, it ispossible to reduce electric power to be inputted (the reduction in powerconsumption). Since a caloric value is also low, it is also possible todiscourage or prevent noise due to a cooling fan or the like (thereduction in noise). In addition, since the LEDs 10 r, 10 g, and 10 bthemselves are lighter and smaller than the high pressure mercury lamp,it is possible to use a circuit to drive the LEDs 10 r, 10 g, and 10 bsmaller than a drive circuit for the high pressure mercury lamp.Consequently, to address or realize a low cost of the projection-typedisplay apparatus, it is more advantageous to use the LEDs 10 r, 10 g,and 10 b as light sources than using the high pressure mercury lamp as alight source.

Since the LEDs 10 r, 10 g, and 10 b are arranged and used as an LEDarray, light having a uniform illuminance distribution is made incidenton the surface of the mirror device 30 that is an object to be lightedof the light source. Therefore, it is unnecessary to provide thedichroic prism unlike JP-A-2003-186110. This is advantageous to addressor realize the reduction in weight and size and the reduction in priceof the projection-type display apparatus.

Moreover, since the LED array is formed by arranging the LEDs 10 r, 10g, and 10 b emitting the respective color lights of R, G, and B, it ispossible to form a color image without providing a dichroic prism tosynthesize different color lights. This is advantageous to address orrealize a reduction in weight and size and a reduction in price of theprojection-type display apparatus.

An intensity of emitted light from the mirror device 30 can becontrolled for each of the micro-mirrors. Thus, for example, sinceemitted light intensities of the respective color lights can becontrolled to predetermined intensities, it is possible to control acolor balance of an image to be projected to a predetermined balance. Inaddition, it is possible to display an image of predetermined brightnesswithout being affected by external factors, such as aged deteriorationof a light source.

When an intensity of emitted light from the mirror device 30 is measuredby the measuring element 40, the measuring element 40 and the absorbingmember 45 are arranged to be replaced with each other, whereby it ispossible to measure an intensity of ineffective light.

Since the modulated light and the ineffective light are in a one-to-onerelation, it is possible to calculate a correction parameter for themodulated light on the basis of the intensity of the ineffective lightnot made incident on the projection lens 70 and control an intensity ofthe modulated light to be made incident on the projection lens 70 to apredetermined intensity.

Since an intensity of the ineffective light is measured, intensitymeasurement for the ineffective light can be performed even while animage is projected. Accordingly, it is possible to prevent decline in animage quality. In addition, the absorbing member 45 is always caused toabsorb the ineffective light when an intensity of the ineffective lightis not measured. Thus, it is possible to discourage or prevent themeasuring element 40 from being deteriorated.

As described above, the measuring element 40 may be arranged to bereplaceable with the absorbing member 45, or as shown in FIG. 6, may bearranged to be replaceable with the reflecting plate 51. According tothis structure, it is possible to measure a modulated light intensitydirectly with the measuring element 40 and measure an accurate modulatedlight intensity. Therefore, it is possible to calculate an accuratecorrection parameter easily and control the modulated light intensity toa predetermined intensity accurately. In addition, when a modulatedlight intensity is not measured, since the measuring element 40 isarranged to be replaced with the original reflecting plate 51, it ispossible to discourage or prevent the measuring element 40 from beingdeteriorated by incident light.

As shown in FIG. 7, the measuring element 40 may be arranged to bedetachably insertable on a path of modulated light between the mirrordevice 30 and the prism 50. According to this structure, when an emittedlight intensity is not measured by the measuring element 40, it ispossible to detach the measuring element 40 from the path of modulatedlight and prevent decline in an image quality without affecting an imageto be projected. In addition, when a modulated light intensity ismeasured, since the measuring element 40 is inserted into the path ofmodulated light to measure the modulated light intensity, it is possibleto measure the modulated light intensity directly and measure anaccurate modulated light intensity. Therefore, it is possible tocalculate an accurate correction parameter easily and control anintensity of modulated light to a predetermined intensity accurately.

As shown in FIG. 8, the reflecting plate may be a reflecting plate 51 ahaving transmissivity to transmit several percent of incident modulatedlight, and the measuring element 40 may be arranged to measure modulatedlight transmitted through the reflecting plate 51 a. According to thisstructure, the measuring device measures an intensity of emitted light(modulated light) transmitted through the reflecting plate. Thus, themeasuring device never affects an image to be projected, and it ispossible to discourage or prevent decline in an image quality. Inaddition, since measurement of an emitted light intensity by themeasuring device can be performed even while an image is projected, itis possible to always discourage or prevent decline in an image quality.

In addition, as shown in FIG. 9, brightness of an image projected on thescreen 71 may be measured by the measuring element 40. According to thisstructure, since it is unnecessary to set the measuring element 40 inthe projection-type display apparatus, it is possible to address orrealize a reduction in weight and size of the projection-type displayapparatus.

A technical scope of the invention is not limited to the exemplaryembodiments described above, and it is possible to apply variousmodifications to the invention within a range not departing from thespirit of the invention.

For example, in the exemplary embodiments described above, the inventionis explained in the application to the structure in which the LED array,which emits color lights of R, G, and B, is used as a light source.However, the invention is not limited to the LED array that emitsdifferent color lights but can also be applied to various otherstructures, such as a structure in which a color wheel is provided in anLED array that emits a white light.

In addition, in the exemplary embodiments described above, the inventionis explained in the application to the structure to calculate acorrection parameter using the measuring element 40. However, theinvention is not limited to the structure using the measuring element 40but can also be applied to various other structures, such as a structurewith which a viewer can input a correction parameter according topreference of the viewer.

1. A projection-type display apparatus, comprising: a solid-state lightsource that emits light; a mirror device that controls an emittingdirection of the light incident from the solid-state light source tothereby subject the incident light to temporal modulation; and aprojecting device that projects the modulated light, wherein the mirrordevice includes micro-mirrors arranged in a matrix shape, thesolid-state light source is configured to be turned on after apredetermined time has elapsed from the micro-mirror turning on.
 2. Aprojection-type display apparatus, comprising: a solid-state lightsource that emits light; a mirror device that controls an emittingdirection of the light incident from the solid-state light source tothereby subject the incident light to temporal modulation, the mirrordevice includes micro-mirrors arranged in a matrix shape; a control unitthat outputs a modulation control signal based on a video signal tocontrol the temporal modulation by the mirror device; an A/D conversionunit that converts an analog signal into a digital signal; and aprojecting device that projects the modulated light, wherein the videosignal is inputted to the control unit via the A/D conversion unit inthe case the video signal is the analog signal, the video signal isinputted to the control unit directly in the case the video signal isthe digital signal.
 3. A projection-type display apparatus according toclaim 2, further comprising: a decoder that decodes the video signal inthe case the video signal is compressed data.